Non-linear resonance in the simplest RLC circuit

We describe an undergraduate experiment demonstrating a non-linear oscillator based on a simple RLC circuit. Non-linearity is introduced by a single, reverse biased, diode. The response curves are described as a function of the generator amplitude and reverse polarization voltage. The oscillator can be modeled making use of the skeleton curve, which relates the resonance frequency with the amplitude of the oscillations, reducing the complexity of the mathematical description. We also give some insights on the physics of the skeleton curve and deduce information about the diode.